
#include <stdio.h>

int main()
 {
   double hig=0.0;
   int i=0;
   double sum=0.0;
   double avg=0.0;
   for(i=0;i<5;i++)
   {
   scanf("%lf",&hig);
   sum+=hig;
   avg=sum/5;
   }
printf("%.2lf",avg);
    return 0;
}
